The present invention relates to the field of direct acting valve assemblies, and in particular to a valve assembly having an improved structure providing for more reliable opening and closing of the valve port.
Direct acting valves are used in a variety of settings and may include a solenoid control to open and close the valve port. Such valves are used, for example, in the control of water flow for ice makers and similar types of low water flow rate devices.
Typical direct acting valves currently in use for these types of applications utilize a conically pointed armature which shuts off the fluid flow by dropping into a concave seating pocket made of rubber. This design requires that the armature and concave seating pocket be closely aligned during shut-off. In current designs the armature is located in a guide tube, with liberal clearance to protect against dirt, and the guide tube is located in the valve body. The concave seating pocket (rubber diaphragm) is located in the valve body. Manufacturing tolerances accumulate to the point that the armature tip will "drag" on the side of the concave seating pocket. This drag causes two failure modes. First, failure occurs as a result of severe misalignment by the armature tip not dropping into the sealing pocket. Second, failure occurs over time when the armature tip will wear a groove in the rubber sealing pocket and a slow leak will develop.
In U.S. Pat. No. 3,818,398, issued to Barbier et al. on June 18, 1974, there is disclosed an electromagnet coil assembly used in a valve assembly. The Barbier et al. patent discloses a structure for a vlave assembly which includes a pointed plunger which is received by an aperture in a disc. The disc is in turn carried by a valve member, and in its lowermost position closes the valve port.
In U.S. patent application Ser. No. 722,170 filed on Apr. 11, 1985, issued as U.S. Pat. No. 4,558,844 to the present applicant, Donahue, on Dec. 17, 1985, there is disclosed a direct acting valve including an upraised sealing seat and a closure member having at one end a pocket containing a valve seal. In the closure position, the end of the closure member having the pocket, and thus the valve seal, is positioned down against the upraised sealing seat.
A variety of pilot operated valve assemblies are disclosed in U.S. Pat. Nos. 4,387,878, issued to Zukausky on June 14, 1983; 4,174,824, issued to Kolze on Nov. 20, 1979; 4,178,573, issued to Swanson on Dec. 11, 1979; 4,175,590, issued to Grandclement on Nov. 27, 1979; and, 3,872,878, issued to Kozel et al. on Mar. 25, 1975. These valves utilize a flexible diaphragm carrying an insert which defines a raised surface acting as a valve closure. The solenoid plunger supports a resilient member, such as rubber, positioned to close the raised surface of the diaphragm insert when the plunger is in its lowermost position. Upon closing the raised valve port, the diaphragm and insert move downwardly against the major valve port, to shut off flow of fluid through the valve. The ratio of solenoid plunger diameter to the diameter of the raised surface of the diaphragm insert is such that close alignment of these diameters is not significant in the pilot operated valves.